Madame Loisel is unhappy with her life because she was born poor when she feels as if she should have been rich.
Madame Loisel is a middle class woman, who for some reason feels that she should have been a wealthy woman. She was born “as if by a slip of fate” into a family of clerks instead of the upper society.
Mathilde suffered ceaselessly, feeling herself born to enjoy all delicacies and all luxuries. She was distressed at the poverty of her dwelling, at the bareness of the walls, at the shabby chairs, the ugliness of the curtains. All those things, of which another woman of her rank would never even have been conscious, tortured her and made her angry.
Nothing is ever good enough for Mathilde. She isn't satisfied with a husband who is a clerk and got her an invitation to a ball, because she doesn't have a dress that she believes in good enough to wear to the event. She believes doesn't have a jewel that is good enough, so she borrows one from a friend who is of a higher class than she is.
Mathilde wants people to envy her. She wants to be looked at.
She had no gowns, no jewels, nothing. And she loved nothing but that. She felt made for that. She would have liked so much to please, to be envied, to be charming, to be sought after.
During the ball, it is as if by buying a dress she can’t afford and borrowing a jewel, she also borrows a life. People look at her. She is beautiful. It is the one thing she does have. So when she is dressed up and has what looks like a pretty necklace, she is the light of the ball.
The necklace turns out to be a fake, just like Mathilde. She is nothing but image—beauty on the outside, nothing real on the inside. When it is real and she destroys her beauty to replace it, it is ironic. It all could have been avoided if she had just had the character to tell her friend the truth that she lost it.